Novel autonomous voltage and current measurement unit for Smart Grids

A novel autonomous voltage and current measurement unit is presented. Due to its high accuracy, communication interface and self-powering feature it is well suited to operate in Smart Grids. Particular attention was paid to its power supply circuits harvesting energy from measured currents and voltages and to the current measurement circuit accepting Rogowski coils and offering a wide measurement range. In order to achieve long term reliability much effort was spent reducing thermal effects inside the unit in case of excessive input currents used as the source of supply energy harvested from the measured signals.